Pestiviruses cause highly contagious and often fatal diseases of pigs, cattle and sheep, which are characterised by damage to the respiratory and gastrointestinal tracts and immune system and can run an acute or chronic course. Infection of the reproductive system may cause embryonic and fetal death, congenital defects and the birth of persistently infected animals. Outbreaks of the diseases associated with pestivirus infections occur in many countries and can cause large economic losses.
The Pestivirus genus of the Flaviviridae comprises three structurally, antigenically and genetically closely related member species: Classical swine fever (CSF) or hog cholera (Francki et al. 1991. Flaviviridae, In the Fifth report of the International Committee on Taxonomy of Viruses, Archiv. Virol. Suppl. 2, Springer Verlag, Vienna p. 223-233); Bovine viral diarrhea virus (BVDV) which mainly affects cattle, and Border disease virus (BDV) which mainly affects sheep (Moennig and Plagemann (1992) Adv. Virus Res. 41: 53-98; Moormann et al., (1990) Virology 177: 184-198; Becher et al. (1994) Virology 198: 542-551). Recent studies indicate that there may be several less well recognised viruses that warrant separate taxonomic classification, perhaps as separate species (Avalos-Ramirez et al (2001) Virology 286: 456-465)
The genomes of pestiviruses consist of a positive strand RNA molecule of about 12.5 kb (Renard et al. (1985) DNA 4: 429-438; Moormann and Hulst (1988) Virus Res. 11: 281-291; Becher et al. (1994) Virology 198: 542-551). However, the positive strand RNA genomes of several cytopathogenic BVDV strains may be considerably larger (Meyers et al. (1991) Virology 180: 602-616; Meyers et al. (1992) Virology 191: 368-386; Qi et al. (1992) Virology 189: 285-292).
An inherent property of viruses with a positive strand RNA genome is that their genomic RNA is infectious, i.e. after transfection of this RNA in cells that support viral replication, infectious virus is produced. As expected, the genomic (viral) RNA of pestiviruses is also infectious (Moennig and Plagemann, (1992) Adv. Virus Res. 41: 53-98).
In 2003 an outbreak of stillbirths and pre-weaning deaths of piglets occurred on two farms in New South Wales, Australia (McOrist et al, (2004) Aust Vet J. 82: 509-511). Key features of the clinical presentation and pathology findings suggested that this disease outbreak was novel and probably due to a virus. Extensive testing for known viruses and some bacteria failed to identify an aetiological agent. To avoid confusion with other important diseases in pigs, the term “porcine myocarditis syndrome” (abbreviated as “PMC”) was ascribed to the disease, and the term “PMC virus” given to presumptive agent. Subsequently, the causative agent was identified as a novel pestivirus. The name Bungowannah is proposed for this new virus.
The present invention addresses a need in the art for methods of detecting and/or treating infections caused by the novel PMC virus.